Back when the early days of personal computing, you did your work on your computer and either printed out the finished work, or stored it to work on later. Early on, cassette tapes were the storage medium of choice as they cassette tape recorders were commonly available, and reasonably affordable. Some computer system did have disk drives, but they were more expensive.
Though cassette tape was the default method of saving your work, the process was fussy, was very hands-on, and worked like this on the NEC PC-8201a:
- plug the tape deck into the computer using the appropriate cables
- on the computer, move the cursor to the file you wanted to save
- press the Save key [f‑2]
- type the file name you wanted the file to be saved as when written to the cassette. Make sure you make note of the file name you enter, exactly, as you’ll need that if you want to load that file back from the cassette
- ensure you have a tape in the cassette recorder and the Record and Play buttons are pressed.
- answer [y] to the ‘Ready?’ question.
The computer will then control the cassette deck using the Remote control port through the cassette cable. It will start the deck, write the file name to the tape, then write the file data to the tape and stop when the file has been written.
Mission accomplished! Good work!
Whew! A lot of things to do to save a file. Now, to get the file back off the tape and back into the computer. Reading (or Loading) a file from tape is pretty much the reverse — you provide the appropriate file name, and when the computer sees it as it plays through all the files on the tape, it will load the requested file, ignoring all the others. Read on to see how it worked with modern equipment.
How it works?
Files were stored sequentially on the cassette — the computer couldn’t automatically fast-forward to the next file. If you were crafty and had a good ear, or used the tape index counter on the recorder and wrote down the ‘location’ of each file as you saved it to tape, you could skip ahead to the appropriate counter index number.
Now let’s do it with modern equipment.
If, like me, you don’t have a working vintage cassette recorder, you’ll have to use a computer or digital audio recorder.
I happened to have a digital microphone with a line in jack.
Depending on the device you use, you will have to turn off or disable any sound filters (low-pass, auto rec. level, etc) as we want to record the pure sound from the computer.
Modern digital recorders generally record in stereo through the line-in port, so you’ll need a stereo splitter cable between the cassette deck and the recording device. That will separate the left and right channels, and give them their own jack. Then plug one of those separated jacks into the computer data cassette cable. One plug on the data cable will be for Data In, another for Data Out. Depending on how the cable was wired, the jack that may mean Data In to the the recording device, OR data in to the computer. Give it a test, one will work, the other won’t 🙂
In my case, the file will be recorded as a digital sound file (WAV format) on a mini SD card, which can then be read by any computer as an audio file. You won’t be able to read the specific data until you load that audio file back into the appropriate computer.
Since the digital microphone doesn’t have a Remote function, I had to manually time the starting and stopping of the recording.
A bonus feature of the microphone, it had a headphone jack so I could monitor the sound coming from the computer as it was starting, sending, and ending the process.
Here’s how it worked:
- same process for recording as above, up to the point of pressing ‘y’ to start the cassette recorder by the remote
- at this point, your computer is waiting for the ‘y’, start recording on the digital device. You’ll hear the computer sending a solid tone.
- once the recorder is recording, then type ‘y’ on the keyboard, and listen to the save process if you’re monitoring through the microphone headphone jack.
- the computer can’t turn off the recording device when the file has finished unless it too has a remote connection (my microphone didn’t) so you’ll have to watch the screen on the NEC to determine when the saving is done, or listen for the quiet ‘click’ of the relay inside the NEC — this relay is what is controlling the remote control cable.
Now that you’ve safely got a copy of your masterpiece (in my case, an unedited version of this blog post) on the SD card, you can move it to your computer, save it to your hard drive, email it to friends, or even link to it in a blog post!
To load your saved masterpiece back into the computer, as mentioned previously, the process is simple:
- select the file on the digital playback device
- press the ‘Load’ button and enter the file name used when you saved the file to the device originally (it’s good to keep notes)
- then when prompted, enter the file name to save the incoming file as. Remember to append the appropriate suffix (.DO, .BA, etc) to the file name or you’ll get an error.
- When prompted on the computer with ‘Ready?’, press play on your digital playback device
- then type ‘y’ to start the computer reading the incoming data file
The computer will tell you when it finds a file by displaying ‘Found filename’. If ‘filename’ matches what you’d entered when you told the computer to Load ‘filename’, the the file will be saved to your computer. Otherwise, the computer will ignore that file and listen for the next one.
Back in the day
So yeah, a very clunky manual procedure with a few obvious fail points.
But it’s neat to play around with and discover that you can still read and write text and BASIC files to audio, just like they did in the latter part of the last century — if you can convince your modern equipment to work like the old-timey stuff does.
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